Self-cleaning filter



July 12, 1949. w. JOKEL 2,475,968

SELF-CLEANING FILTER Filed Jan. 8, 1945 3 Sheets-Sheet 1 ATTORNEY July12, 1949. w. JOKEL 2,475,968

SELF- CLEANING FILTER Filed Jan. 8, 1945 v 3 Sheets-Sheet 2 VINVENTOR.

lUittw/m JoKeL BY f r/ aafpa.

.ATrORNEY Patented July 12, 1949 UNITED STATES PATENT OFFICE.

SELF-CLEANING FILTER William Jokel, Brooklyn, N. Y.

Application January 8, 194.5, Serial No. 571,824

Nil. tltll This invention relates to improvements m selfcleanlng filtersfor liquids in which the liquid to be filtered ls'fecl under pressureand the filterbed may be cleaned by a, reverse flow oi the liquid, andmore particularly comprises an improvement upon the type of flltershownand described ln my United States Letters Patent $2,366,112, datedDecember 26, loss, which discloses a fllter=medlum contelned in areclprocetlng hollow plstoo movable automatically by pressure ceused loyclogging of the filter-heel from filtering position to self-cleaningposition sod also movable re versely to normal filtering position by erestore tlon of permeability of the filter-hell clue to the cleaningthereol,

Que o? the ohjects oi my present invention is to provide a filter or thetype specific in which the lrzteke how of liquid will he contlhuous, thestoppage thereof during the cleaning period being avoided, and thevalves used to stop such intake flow will he eliminated.

Another object of my invention is to provide a filter of the typespeclfled ln which the reverse filter-cleansing flow of the liquid willcomprise the passage through the filter bed and filterihs medium inreverse direction of o predetermined quantity of liquid under pressuresumclent to provide a thorough cleaning of the filter heal and filteringmedium instead of relying upon the per= meability of the filter-bed torestore the parts to normal position.

Still another object of my invention is to pro= vlde a device of thecharacter specified in which the restoration of the parts to normalfiltering condition will be positively accomplished auto-= maticallyupon the passage under pressure of a given quantity of llquld 321reverse direction through the filter-hed 4 Still another object of myinvention is to pro= vide a construction in which undesirablebranchpipes from the intake of the mter will he elim= ineted.

Still another object of my lnventlon is to provide a construction inwhich the automatic restoring movement of the bed-carrying piston orvessel from cleansing to filtering position will be positive andinstantaneous.

Another object of my invention is to provide, in comblnatlon with mysaid spring-pressed reciprocable piston, an automatic locking deviceadapted to positively hold the piston in cleaning position until aquantity of liquid which may be precisely predetermined and sufllcientfor cleansing purposes is passed through the filter-bed in reversedirection.

Another object oi? my invention is to utilize means to provide to! a,continuous non-stop flow o! the liquid being filtered and especially forthe continuity of pressure flow of the liquid during the period when thefilter is out of sctlon for self clesrllng.

Still smother object of my invention is to provide a structure whichwill he adopted for large scale operations With these end other objectsin view, the lh= ventloo. crashes the combination of members andarrangement of parts so combined as to cc=oct and scope-rem with eachother in the performalise of the functions and the accomplish-= most ifit re results herein contemplated, and comprises he one oi itsadaptations the species or preferred term illustrated in theaccomocu:5"= lug drawings, which may be interpreted as lllus tretlve andnot is e limiting sense. Various changes may he made to. the details ofcoostructics without departing from the spirit of the invention asdefined by the sppeuded claims.

Fig. l is s vertlcsl section 02 my filter in normoi filtering pcsltlom;

Fig. 2 ls e. similar view of the filter shown in Fig. 1 with the partsin self-cleaning position;

Fig. 3 is a modified form of filter in normal filtering position andshowing the intake and actuating sprc' lo inverted position and themeans for determining the quantity of self-clean-= lug liquid is ottezl;

Fig. l is 2. similar View of the modified form of filter shown lo; Fig.3 with the parts in self= cleansing sitloo;

Fis. 5 is a sectional view of another modified form of my invention inwhich the filter is dis posed in horizontal position and the filter-bedis positioned parallel to the axis of movement of the plstou mad thefilter parts are in normal filtering sltlou;

Pier. 8 ls a similar section of the device shown in Fig. 5 with theparts in self-cleansing positics; and

Fig. l is a section on the line l-l of Fig. 1 looking in the dlrectlonof the arrows.

Referring to drawing Figs. 1. and 2, this filtering device comprises thefilter casing C having spring pressure operable against the dynamicpressure of the infiowing liquid from the main inlet R, and toyieldingly hold the piston or vessel I in its normal working orfiltering posltion against such dynamic pressure. I is a filterbedpreferably comprising a strainer which may be formed of wire-netting,perforated sheet metal or other suitable material. One or moreof suchstrainers preferably extend transversely across the longitudinal axis ofthe cavity of the vessel and a body or layer of loose filteringmaterial; is supported on such strainer or strainers; As shown, thepiston I has three ports comprising an inlet port I located, as shown,above the filter-bed i8, and an outlet port 8 located at the oppositeside or below the. filter-bed. Filtered liquid in the normal filteringoperation of the filter passes through the port 3. ,A port 8 is alsoprovided liquid-circulating ports 8 and II adapted to circulatefilter-cleansing liquid in the casing C and cooperate with reciprocatingauxiliary piston 2 to provide liquid-measuring mechanism for thecleansing liquid. The casing C also has three additional conduits, theconduit 8 being adapted to cooperate with the port 1 in providing forthe continuous flow of liquid from the pistoninlet port I to thefilter-bed during the normal filtering operation of the device, theconduit 4 being arranged to receive and conduct the filtered liquid tothe exhaust P during such normal filtering operation, and the conduit 8being adapted to cooperate with the casing inlet R and the piston port 9to conduct the incoming liquid in reverse flow when the piston of thedevice is moved to the position shown in Fig. 2. The casing C also ispreferably provided with a groove I! to provide a housing for one arm ofa locking mechanism adapted to engage and disengage with a notch I3 inthe piston I.

As illustrated, the said locking mechanism comprises a spring-pressedbell-crank l8 pivoted on pivot H; to the casing C and adaptedautomatically to latch the piston I in self-cleansing position when thesame is moved thereto. As shown, the bell-crank has an upright arm I8housed and movable in groove I8 and provided at its upper end with ahooked nose l8 which, upon pivotal movement of the bell-crank lever.isadapted to engage and disengage withthe notch I3 in the-piston. Theother arm. it of the. bell-crank I3 projects outwardly from thepivot I8"and is pressed downwardlyby a fiat'spring I'lto cause the. arm I3 to beresiliently heldzin position to engage the notch I3 when the piston, isloweredin the casing. The fiat spring I 2i' is,..as shown, fixed at oneend to the ring II mounted on the inner wall of. the casing and has itsfree end pressingagainst the said 'arnrll The said rin H functions asanabutment for one end of the coil spring and as a limiting device forthe movement of the piston I, and also, comprises a stop for causingregistration. of the hookednose I 8 0! the arm I8 with the notch l8 intheouter wall of the piston I. I

My preferred means for automatically releas- 4. arm with the pistonl'comprises an auxiliary reciprocating piston 2 provided with a port 28adapted in the normal filtering position of the filter to register withthe liquid circulating port 2| of the casing. The port 2i is connected,as shown, by conduit I5 to permit circulation of liquid from the port 5through the ports 2| and 28 to the shallow-chamber C beneath theauxiliary piston 2, which'will thereupon be raised, as illustrated inFig; 2, and will engage and raise the arm I3 of the bell-crank is .whichwill swing the arm' l3 to release the nose I3 from the piston-notch I3,thus releasing the piston I-and permitting the coil spring It to movesaidpiston I upwardly into the normal filtering position shown inFig. 1. I

The filter shown in Figs. 1 and 2 operates as follows: During the.normal filtering operation of the filter, the raw liquid enters thecasing C at R and is forced by pressure to pass through groove 8 in thecasingand port I in the piston or vessel I, and thence through thefilter-bed comprising the strainer III and body of loose filteringmaterial. The raw-liquid is thus freed from admixedimpurities or foreignbodies-and therein above the piston 2 until the level thereof reachesthe main exhaust port P. The area of the port P is preferably limited inorder to' cause an upward pressure by such liquid against piston I andto force the piston 2 downwardly. When the chamber C is filled therewill be stored within the same a quantity of filtered liquid whichpresses the piston! downwardly until it shall have moved down to itsextreme posi-v tion at the bottom of the casing; In this way, a constantnon-stop flow of cleansed liquid is maintained in the filter. In thenormal filtering position of the device, the liquid inlet port 9 of thepiston I which admits raw liquid to the piston for filter-cleansingpurposes, will be out of registration with the conduit 8 and thus iscompletely closed by the casing wall and'conduit 8 is also completelyclosed and blocked to access of liquid by the 'wall of the piston, asshown in Fig. 1; When, however, the filtering medium or layer on thestrainer becomes clogged by impurities or foreign bodies, the pressureof the raw liquid fed at R will overcome the, resistance and compressthe spring II to depress the piston I into the position shown in Fig. 2.When the piston is thus lowered the hooked upper end ot'the arm H, whichis constantly Dressed toward the wall of the piston, will slide into thenotch IS in the side wall of the piston i and the piston will be latchedin its'lower extreme position. The connection or communication of theconduit 6 with the piston ously'; caused to register :with the port 8located below' the" filter-bed -in: the piston. The raw liquidv thuspasses-through conduit 8 and port 9 and flows in the. reverse directionupwardly through the strainer, lifting and rinsing the filteringmaterial supported thereon. Said cleansing liquid with all theimpurities of the filterbed and strainer is now initially passed throughing the latching engagement of the bell-crank pistonport 1, casing port5 and through pipe I 2 show) l5, port 2| and port 20 into the shallowcompartment C beneath the auxiliary piston 2 and functions to releasethe piston l. Thus, the piston 2 is lifted upwardly until the uppersurface thereof engages the bell-crank lever arm l3 to move thepiston-latching arm l3 thereof out of engagement with the notch 13. Atthis time, the clogging and resistance to pressure of the impurities inthe strainer and filter layer being eliminated. the coil spring I willshift the piston I upwardly to its normal filtering position, whereuponthe entrance to the conduit 8 will be closed and the filtering liquidwill again be fed through conduit 6 and port 1 above the filtering bed.In this filtering position, the port 5 of the conduit l5 will be placedinto registration with the conduit I! of the piston which communicateswith the main waste pipe W, and upon further operation of the filter thenormal pressure of liquid above the auxiliary piston 2 will force saidpiston 2 downwardly and will cause the reverse outward movement of theimpure liquid through the conduit l5 and to the waste pipe W. The normalfiltering or working of the filter will then continue until the straineror filter bed is again clogged, whereupon the cycle will be repeated. V

In the drawings, Figs. 3 and a show a different way to locate the coilspring or similar means, thus avoiding its constant overload. Forsimplification, in this drawing the retarding or timing device has beenomitted. This filter comprises the casing C with three main ports, R forrawliquid intake, P for purified liquid outlet, W for waste-exhaust andthree conduits d, 5, 3 (all Working on the same principle as Figs. 1 andA hollow piston i is snugly fitted within the casing and is freelyaxially and reciprocatingly-rnovable therein. The piston has three ports5', l! and iii cooperating with the casing conduits as hereinafterspecified. A. coil spring 8' is inserted in casing C between its innertopend and the top of hollow piston B. An adjus ing-ring i3 fixes thepath of piston i downwardly and thus brings ports t and id, as Well asconduits 6 and 5 into registration. Pin 92 is limiting the movement ofpiston l upwardly, forcin the aligned ports 9' and it andcorrespondingly i3 and E5 to register, when piston i has moved into itsextreme top-position. A strainer with filtering layer is provided acrosscavity of piston i in the same way as in Figs. 1 and 2 shown anddescribed.

The operation of the filter shown in Figs. 3 and i is as follows:

Fig. 3 shows normal filtering position. The raw or crude liquid is fedin by pressure at r and flows through conduit ti and ports 6 and throughstrainer H and its layer downwardly into the lower chamber of the cavityin piston i and is discharged cleaned over port i at P. When thestrainer and its layer become clogged up with retained impurities orforeign bodies from the raw-liquid, the inner resistance in the strainerand layer will, through over-pressure of the incoming raw-liquid,overcome the tension of spring 3 and will shift piston i to its topposition, the movement being limited and the position fixed by pin l2thereon. In this position, conduit 5' is shut off from port 6' and thepiston-cavity while ports 9' and HI and correspondingly ports 4' and 6',which are aligned, come into registry. The crude liquid will now flowreversely (Fig. 4) through 9 and III into piston cavity underneath thestrainer and thence upwardly through strainer I I, lifting and rinsingits layer to clean the same from its adhering impurities, and thereafterflowing through ports 8' and conduit 4 through casing cavity to conduitW, as waste. Meanwhile port I and conduit P are shut ofi by the pistonwall. .As soon as the resistance in the strainer unit has ceased, spring3' moves piston 2' back into its lower position (Fig. 4), shutting offpiston port l0 from communication with conduit 9, also cutting oficonduit 4' from piston port 6' and re-establishing the communicationbetween inlet R, conduit 5' and port 6' to conduct liquid to the upperside of the strainer and while port I and conduit P underneath the planeof the strainer are movedinto registration, thus continuing the normalcleaning operation. Waste conduit W remains continually open to theupper part of the casing but this casing portion is disconnected fromthe piston and the filtering flow of liquid in the normal filteringposition shown in Fig. 3.

Figs. 5 and 6 are sectional views of a device suitable for large-scalestructural designs for providing a continuous supply of cleaned liquidfor recovery of foreign bodies from raw-liquid in which they had beensuspended and includes a latching device for retarding the returningmovement of the piston and thus increasing the cleaning period to securea perfect cleaning without disturbances due to vibrations. These viewsalso include the provision of ball hearing elements between casing andpiston or vessel=walls to provide controlled easy movement of a heavypiston and to cause the actuating coil spring to be placed under low andtransitory compression only, and a modified disposition of the strainerand its loose filtering layer, showing the strainer with verticalpartitions extending across the strainer and some- What higher than thefilter layer, for equalizing the filtering layer all over the strainer.in Figs. 5 and ii reference character C designates the casing of thefilter which has three compartments, the first one being immediatelyadjacent to the main-intake PF, and partitioned from said intake by oneend of a hollow piston 56 which is fittingly inserted in the casing Cand freely movable axially in it. The second chamber is located betweenouter bottom of the hollow piston or vessel 52 and another piston 5%,which is axially movable in the end of casing ll opposite to the inlet RPiston 56 has two ports: one

- comprising port :12 aligned with conduit 5i in the till casing and theother port it being aligned with the sludge drains l d and i5. The thirdcompartment is formed by piston 6% and the inner bottom of the casing0*. All these three chambers vary in volume according to the endpositions of the pistons 56 and 656i. Casing C has a maininlet R for theraw-liquid, a main outlet P for the cleaned liquid and a main exhaust Wfor the waste and for the recovery of the solid particles floating inthe concentrated liquid suspension. 52, 5i, 5%, 65 are conduits in thecasing 0 In piston hi there are four ports 53, 56, 58 and ti l and aconduit 55. In the normal working position, the pairs of ports 52, 53,58, 59, 58 and 517 and W '5 l are aligned and in register, the ports 5l56 and 6-6l being shut ofi. In the cleaning period, ports 52-53, 545|-W -5fi-585@ are shut off, whereas 60'6l and 56-5? communicate.Inserted in and extending axially along the cavity of vessel or piston5| is a strainer 62, consisting of mesh-sieve, perforated sheet or thelike, consisting mainly of metal or any suitposition of vessel sel 5|,even in large designs; The coil spring 10, inserted in casing C betweenring 58 and bottom-outsidev of vessel 5| acts yieldingly against thelatter. A ringlike prong 11 on the outer bottom of vessel 5|, whencontacting ring 58, fixes one end-position of vessel 5|, whereas buffers15 in the intake-end of easing C (keeping the intake-conduit 52 open)fix the other extreme In the same way the two end-positions of piston 54are fixed by ring '55 on the one hand and bythe inner bottom ofthecasing C and is freely movable axially in it. The latching and retardingdevice comprises the pin 59 or the like on outer bottom of vessel 5|, apin 55 on the opposite-top of the piston 54 and one or more fiat springs51 or the like projecting radially from the fixed ring 58. Pin 55 on topof vessel 5| keeps the sectional area of the intake normal, but opens itwide in the self-cleaning period, when the vessel moves into its latchedcleaning position. 14 and 15 are sludge-drain-bolts.

The filter of Figs. 5 and 6 operates as folfows:

Referring to Fig. 5, the raw-liquid enters the filtering casing at R andflows over conduits 52 and 53 and downwardly through the layer offiltering material and strainer, thence passing through port 58 andconduit 59, filling the second chamber between both pistons 5| and 54and flowing out at P as cleaned liquid. The surplusliquid which does notpass through the relativelynarrow area of P will push the piston 54 backto its end-position at the casing-bottom, as shown in said Fig. 5.

Referring to Fig. 6, when the strainer becomes clogged up, the pressureof the raw-liquid at R moves piston 5| in the direction of flow tillbutlerprong 11 strikes adjusting-ring 58 and pin will then latch in thesprings 51, or in similar device.

Now 52-53 and 58-59 are shut off, whereas Bil-5| and 55-51correspondingly register. Movement of the vessel 5| causes pin 55 toopen inlet R wide for increasing the speed of the liquid to rinse thestrainer and its layer. The raw-liquid from R now flows reversely overGil-5| upwardly through the strainer, rinsing it and lifting andbubbling its layer, then flowing over 55-51 under pressure into thechamber between piston 54 and bottom of casing C". As there is noexhaust open,

piston 54 with its latching pin 55 will move towards the fiat-springs51, bending the springs into open position and striking the latching-pin59 and so allowing coil spring to shift the piston 5| back. into itsworking position shown in Fig. 5 in which ports 6l-50 and 55-51 are shutoff and communication is re-established between the channels at conduits52-53-58-59 and 51-54 and exhaust W. The normal working or filteringcondition thus starts again, as described hereinabove, with the normalfiow downwardly, and pin 5, narrowing the area of R? for normalpressure, with the cleaned liquid discharging at P and the surplus of itaccumulating in the second compartment to move piston 54 into itsextreme posi- 8. tion at the bottom of the casing C thus forcing out thewaste, which had been pressed into the compartment between piston 54 andthe casing in the self-cleaning period through conduits 51-54 5 to bedischarged at W. The latching device will measure the cleaning period,and unforseen and uncontrolled oscillating vibrations of the coil spring10 will be avoided. The dimensions of the two chambers in casing Cbetween its bottom and the locking end position of the hollow piston 5|may be adjusted, as desirable, and the areas thereof can be calculatedto produce the bestresults. This filter will thus work in the describedcycle of movement for long periods without being supervised and withoutrepairs or replacing parts.

Having described my invention, I claim:

1. A self-cleaning filter comprising, in combination, a casing adaptedto be insertedin a liquid circulating system, said casing having acylindrical internal chamber providedv with a raw-liquid inlet andhaving a filtered-liquid outlet positioned in spaced relationship tosaid inlet, a reciprocable hollow piston in said casing-chamber arrangedbetween. said raw-liquid inlet and her into a raw-liquid chamber at theouter side of one end of said piston and a, filtered-liquid chamber atthe outer side of the opposite end thereof, said piston being movablealternately in said casing chamber into filtering and filtercleaningpositions and having an internal filtering chamber provided with a massof filtering medium and supporting means therefor mounted to extendacross said filtering chamber and to areas, a feed conduit connectedwith the casing for feeding raw liquid from said raw-liquid chamber ofthe casing to said raw liquid area of the filtering chamber of thepiston, said feed-conduit having inlet and outlet portions communicatingwith said raw-liquid chamber, a filtered-liquid conduit connected withsaid casing in spaced relationship from said raw-liquid feed conduit,said filtered-liquid conduit having its outlet portion communicatingwith said filtered-liquid chamber and its inlet portion communicatingwith the internal surface of the casing facing said piston, said pistonhaving at one end thereof in its side wall a piston-feed port having itsinlet end adapted in filtering position of the piston to register withthe outlet portion of said rawliquid feed conduit and having its outletend communicating with said raw liquid area of the piston, whereby insaid filtering position raw liquid is passed to said filtering area, asecond port in the side wall of the piston having its inletcommunicating with said filtering liquid area and having its outletcommunicating with said filtered liquid conduit, said filteredliquid-conduit being 60 openable and closableby said movement of thepiston and being adapted, when the piston is in filtering position, topass filtered liquid to the outlet, a third conduit connected with saidcasing and having an inlet portion communicating withsaid filteredliquidarea and in reverse direction filtered-liquid outlet to dividesaid casing cham- Y divide the same into raw liquid and filtered liquid7 I 9 through said filtering medium to clean the same, a fourth conduitconnected with said casing and having an inlet port communicating withsaid casing chamber and adapted, in cleaning position of the piston, toregister with said feed port of the piston and to remove impure liquidtherefrom, a spring-supporting means positioned within said casingchamber, a spring mounted on said supporting means and adapted toyieldlngly press said piston to filtering position and also adapted,upon counterpressure of the liquid, to be compressed and to permitmovement of said piston to filter cleaning position.

2. A self-cleaning filter as claimed in claim 1 in which latching meansare mounted within the casing chamber beneath said piston to latch thesame upon movement thereof into cleaning position by saidcounterpressure of the liquid, a liquid circulating conduit for impurewater is connected with the casing, means is also mounted withinREFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 864,810 Taylor Sept. 3, 19071,246,850 Best Nov. 20, 1917 1,682,757 Hopkins Sept. 4, 1928 2,253,690Dalrymple Aug. 26, 1941 2,338,417 Forrest et a1. Jan; 4, 1944 2,366,112

Jokel Dec. 26,1944,

